benchmark.yml

name: Benchmarks

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  benchmark:
    runs-on: ubuntu-latest
    
    steps:
    - uses: actions/checkout@v4
    
    - name: Set up JDK 17
      uses: actions/setup-java@v4
      with:
        java-version: '17'
        distribution: 'temurin'
        cache: maven
    
    - name: Run benchmarks
      run: |
        ./mvnw clean test-compile exec:java -P benchmark -Djmh.options="-wi 2 -i 3 -f 1 -rf json -rff benchmark-results.json"
    
    - name: Process benchmark results
      if: always()
      run: |
        if [ -f benchmark-results.json ]; then
          echo "## Benchmark Results" >> $GITHUB_STEP_SUMMARY
          echo '```' >> $GITHUB_STEP_SUMMARY
          
          # Extract and display results with jq
          jq -r '.[] | "\(.benchmark): \(.primaryMetric.score) ± \(.primaryMetric.scoreError) \(.primaryMetric.scoreUnit)"' benchmark-results.json >> $GITHUB_STEP_SUMMARY
          
          echo '```' >> $GITHUB_STEP_SUMMARY
          
          # Check for performance regressions (fail if any benchmark takes >50ms)
          FAILED=0
          while IFS= read -r line; do
            SCORE=$(echo "$line" | jq -r '.primaryMetric.score')
            BENCHMARK=$(echo "$line" | jq -r '.benchmark')
            
            # Convert to integer for comparison (assuming milliseconds)
            SCORE_INT=$(echo "$SCORE" | cut -d. -f1)
            
            if [ "$SCORE_INT" -gt 50 ]; then
              echo "❌ Performance regression detected in $BENCHMARK: ${SCORE}ms exceeds 50ms threshold" >> $GITHUB_STEP_SUMMARY
              FAILED=1
            fi
          done < <(jq -c '.[]' benchmark-results.json)
          
          if [ "$FAILED" -eq 1 ]; then
            echo "::error::Performance regression detected - one or more benchmarks exceeded the 50ms threshold"
            exit 1
          else
            echo "✅ All benchmarks passed performance thresholds" >> $GITHUB_STEP_SUMMARY
          fi
        else
          echo "::error::No benchmark results found"
          exit 1
        fi
    
    - name: Upload benchmark results
      if: always()
      uses: actions/upload-artifact@v4
      with:
        name: benchmark-results
        path: benchmark-results.json
        retention-days: 30
    
    - name: Comment PR with benchmark results
      if: github.event_name == 'pull_request' && always()
      uses: actions/github-script@v7
      with:
        script: |
          const fs = require('fs');
          
          if (!fs.existsSync('benchmark-results.json')) {
            console.log('No benchmark results found');
            return;
          }
          
          const results = JSON.parse(fs.readFileSync('benchmark-results.json', 'utf8'));
          
          let comment = '## 📊 Benchmark Results\n\n';
          comment += '| Benchmark | Score | Error | Unit |\n';
          comment += '|-----------|-------|-------|------|\n';
          
          let hasRegression = false;
          
          results.forEach(result => {
            const score = result.primaryMetric.score;
            const error = result.primaryMetric.scoreError;
            const unit = result.primaryMetric.scoreUnit;
            const benchmark = result.benchmark.split('.').pop();
            
            // Check if score exceeds threshold
            const emoji = score > 50 ? '🔴' : '🟢';
            if (score > 50) hasRegression = true;
            
            comment += `| ${emoji} ${benchmark} | ${score.toFixed(3)} | ±${error.toFixed(3)} | ${unit} |\n`;
          });
          
          if (hasRegression) {
            comment += '\n⚠️ **Performance regression detected**: One or more benchmarks exceeded the 50ms threshold.\n';
          } else {
            comment += '\n✅ **All benchmarks passed** performance thresholds.\n';
          }
          
          // Find and update or create comment
          const { data: comments } = await github.rest.issues.listComments({
            owner: context.repo.owner,
            repo: context.repo.repo,
            issue_number: context.issue.number,
          });
          
          const botComment = comments.find(comment => 
            comment.user.type === 'Bot' && comment.body.includes('📊 Benchmark Results')
          );
          
          if (botComment) {
            await github.rest.issues.updateComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              comment_id: botComment.id,
              body: comment
            });
          } else {
            await github.rest.issues.createComment({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
              body: comment
            });
          }